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Underwater crop circle mystery solved

The rippling geometric sand patterns in these underwater circles are nearly six feet in diameter and almost 80 feet below sea level.

One of the coolest stories from last week (September 18, 2012) introduced the world to what many are now calling an underwater crop circle. Of course, these sea floor circles have nothing to do with crops, but they are intricate circles, reminiscent of the elaborate crop circles that sometimes turn up in farmers’ fields. Japanese photographer Yoji Ookata captured the photos below while on a dive near Amami Oshima at the southern tip of Japan. He said the rippling geometric sand patterns are nearly six feet in diameter and almost 80 feet below sea level.

Image Credit: Yoji Ookata

Image Credit: Yoji Ookata

Ookata brought colleagues and a television crew to study the mysterious underwater circles further. They found that the artist was a small puffer fish who, using only his flapping fin, tirelessly worked day and night to carve the circular ridges.

The photo above shows the artist: the puffer fish. In Japan, these fish are considered a delicacy, despite the fact they can be poisonous. According to the blog Spoon & Tamago, which I believe is where this story originated, this fish even takes “small shells, cracks them, and lines the inner grooves of his sculpture as if decorating his piece.”

Apparently female puffer fish are attracted by the grooves and ridges. They mate and lay eggs in the center of these undersea circles.

Puffer fish at work making a circle. The circles are apparently for mating purposes. Female puffer fish lay their eggs in the centers of them. Image Credit: Yoji Ookata

Bottom line: In September 2012, a story began circulating about underwater “crop circles,” which are apparently made by puffer fish. Japanese photographer Yoji Ookata discovered them and later brought back a film crew and others to study them. The story appeared in the blog Spoon & Tamago on September 18, 2012.

Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.